Automatic grader for sorting objects according to brightness and color tones

ABSTRACT

A system and apparatus for grading and sorting tobacco leaves and other objects according to brightness and two color tones are provided. The tobacco leaves or objects are caused to traverse a background plate of known color and both are impinged by polychromatic light. The light reflected therefrom in three distinct spectral bands is detected and analyzed according to a predetermined mathematical relationship to compare the brightness and two color tones of the said leaves or objects to standards which are selectively dialed in to the apparatus. Logic circuitry is provided to constrain acceptance or rejection of the leaves or objects by the system in response to a determination that at least one of the characteristics of brightness and two color tones exceeds a predetermined deviation from the preset standards. One of the spectral bands is chosen to provide uniform reflectivity from the series of leaves or objects being sorted to normalize the size of the various objects to that of the background surface.

limited States Patent Perkins, 1H

[ Dec. 17, 1974 AUTOMATIC GRADER FOR SORTING Inventor:

Assignee:

Filed:

Appl. No.:

Joseph R. Perkins, III, Burke, Va.

AMF Incorporated, White Plains,

May 15, 1973 U.S. Cl 209/111.6, 209/1 15, 356/221,

Int. Cl. B07c 5/342 Field of Search 356/51, 221, 222, 229,

References Cited UNITED STATES PATENTS Primary ExaminerAllen N. Knowles Attorney, Agent, or Firm-George W. Price; Charles J. Worth [5 7 ABSTRACT A system and apparatus for grading and sorting to bacco leaves and other objects according to brightness and two color tones are provided. The tobacco leaves or objects are caused to traverse a background plate of known color and both are impinged by polychromatic light. The light reflected therefrom in three distinct spectral bands is detected and analyzed according to a predetermined mathematical relationship to compare the brightness and two color tones of the said leaves or objects to standards which are selectively dialed in to the apparatus. Logic circuitry is provided to constrain acceptance or rejection of the leaves or objects by the system in response to a determination that at least one of the characteristics of brightness and two color tones exceeds a predetermined deviation from the preset standards. One of the spectral bands is chosen to provide uniform reflectivity from the series of leaves or objects being sorted to normalize the size of the various objects to that of the background surface.

82 Claims, 46 Drawing Figures PATENIEU W 3,854,586

sum 01 or 4o REJECT TIMING LOGIC BLASTJ I FRONT l PANEL REJECT CONTROLS @l a 3 TO FIG. 50

PATENIEI; BEE! 71974 saw 07 or 401;

PATENTEL'J 7 7 saw "09 0F 4() FIG 50 \UI\ l 2 M Q E I VAN A A m 5 m $xw s s s e M a 0mm E SSS mw Tc: C A DE PF. US

TO FIG. 5B 

1. Transducer means determining the relative brightness and color tones of articles to predetermined standards and classifying same into categories comprising: a background surface having a predetermined color; source means impinging polychromatic light on the obverse face of said background surface to reflect light therefrom in both the presence and absence of articles on said obverse face; detector means receiving reflected light from said obverse face in first, second and third bands of the spectrum and producing, for each band, first output parameters representative of the respective intensities of reflected light in each said band in the presence of an article on said obverse face of said background reference; reference means storing a second parameter for each band representative of the intensity of reflected light in each band in the absence of an article over siad obverse face; differential means operating on said parameters and producing, for each band, a third parameter representing the magnitude of the difference of said first and second parameters; means modulating said third parameter for each band to vary the magnitude thereof by predetermined interrelated scalar multipliers; summing means operating on said modulated third parameters and producing the sum thereof; control means providing, as said predetermined standards, comparison parameters defining divisions of relative brightness and color tones, said divisions defining a plurality of quality zones of known color characteristics for which said articles might qualify; selection means designating said zones as acceptable and unacceptable; comparison means comparing said comparison parameters and said sums of said third parameters determining the presence and absence of said articles over siad obverse face of said background surface and the zone for which said articles qualify; and correlating means responsive to said selection means and said comparison means classifying said articles into acceptable and unacceptable categories.
 2. The invention defined in claim 1, wherein said divisions of relative brightness and color tones comprise a bright and dark division line and two color division lines, said division lines intersecting to define said quality zones; and adjusting means in said control means constraining said division lines in selectively oriented relative positions to vary selectively the color characteristics defined by each said zone.
 3. The invention defined in claim 2, wherein said control means further includes logic means responsive to said adjusting means constraining said modulating means to correlate said scalar multipliers with said orientation of said division lines.
 4. The invention defined in claim 1, wherein said summing means includes integrating means sequentially integrating said third parameter for each said spectral band over respectively predetermined intervals correlated to said respective scalar multipliers and storing the sum of such integrations in discreet storage means correlated to each of said division lines; and said control means further including sampling means constraining said discreet storage means to apply said sums of said third parameters to said comparison means in synchronism with the respective correlated comparison parameters for said division lines.
 5. The invention defined in claim 4, wherein said divisions of relative brightness and color tones comprise a bright and dark division line and two color division lines, said division lines intersecting to define said quality zones; and adjusting means in said control means constraining said division lines in selectively oriented relative positions to vary selectively the color characteristics defined by each said zone.
 6. The invention defined in claim 5, wherein said control means further includes logic means responsive to said adjusting means constraining said modulating means to correlate said scalar multipliers with said orientation of said division lines.
 7. The invention defined in claim 1, wherein said detector means provide a fourth output parameter for each said band representative of the intensity of reflected light in the absence of an article over said obverse face; said differential means presenting the difference in said second and fourth parameters to said summing means as modulated by said modulating means for each said baNd to the exclusion of the other said bands; said summing means including update storage means for storing said modulated difference in said second and fourth parameters; and update switch means selectively connecting said update storage means with said reference means to update the magnitude of said second parameter with said modulated difference in said second and fourth parameters for each said spectral band.
 8. The invention defined in claim 7, wherein said divisions of relative brightness and color tones comprise a bright and dark division line and two color division lines, said division lines intersecting to define said quality zones; and adjusting means in said control means constraining said division lines in selectively oriented relative positions to vary selectively the color characteristics defined by each said zone.
 9. The invention defined in claim 8, wherein said control means further includes logic means responsive to said adjusting means constraining said modulating means to correlate said scalar multipliers with said orientation of said division lines.
 10. The invention defined in claim 7, wherein said summing means includes integrating means sequentially integrating said third parameter for each said spectral band over respectively predetermined intervals correlated to said respective scalar multipliers and storing the sum of such integrations in discreet storage means correlated to each of said division lines; and said control means further including sampling means constraining said discreet storage means to apply said sums of said third parameters to said comparison means in synchronism with the respective correlated comparison parameters for said division lines.
 11. The invention defined in claim 10, wherein said divisions of relative brightness and color tones comprise a bright and dark division line and two color division lines, said division lines intersecting to define said quality zones; and adjusting means in said control means constraining said division lines in selectively oriented relative positions to vary selectively the color characteristics defined by each said zone.
 12. The invention defined in claim 11, wherein said control means further includes logic means responsive to said adjusting means constraining said modulating means to correlate said scalar multipliers with said orientation of said division lines.
 13. The invention defined in claim 1, wherein the reflectivity in one of said spectral bands from said articles is substantially uniform to normalize the relative size of said articles to the size of said background.
 14. The invention defined in claim 1, wherein said correlating means comprises: digital processing means; program clock means coordinating said processing means with said control means, said modulating means, said selection means and said comparison means; first register means responsive to said clock means and said control means for storing a digital data representation of the determinations of said comparison means; second register means controlled by said clock means for receiving said data from said first register means and transferring said data to said selection means; first decoding logic means in said selection means for operating on said data to provide an indication to said processing means of the presence, absence, acceptable or unacceptable status of a given article over said obverse face of said background; instruction generating means in said processing means supplying instruction data to said second register means; and second decoding logic means driven by said second register means in response to said instruction data for providing command signals indicative of the acceptable or unacceptable status of a given article.
 15. The invention defined in claim 14, wherein the reflectivity in one of said spectral bands from said articles is substantially uniform to normalize the relative size of said articles to the size oF said background.
 16. The invention defined in claim 2, wherein the reflectivity in one of said spectral bands from said articles is substantially uniform to normalize the relative size of said articles to the size of said background.
 17. The invention defined in claim 3, wherein the reflectivity in one of said spectral bands from said articles is substantially uniform to normalize the relative size of said articles to the size of said background.
 18. The invention defined in claim 4, wherein the reflectivity in one of said spectral bands from said articles is substantially uniform to normalize the relative size of said articles to the size of said background.
 19. The invention defined in claim 5, wherein the reflectivity in one of said spectral bands from said articles is substantially uniform to normalize the relative size of said artices to the size of said background.
 20. The invention defined in claim 6, wherein the reflectivity in one of said spectral bands from said articles is substantially uniform to normalize the relative size of said articles to the size of said background.
 21. The invention defined in claim 7, wherein the reflectivity in one of said spectral bands from said articles is substantially uniform to normalize the relative size of said articles to the size of said background.
 22. The invention defined in claim 8, wherein the reflectivity in one of said spectral bands from said articles is substantially uniform to normalize the relative size of said articles to the size of said background.
 23. The invention defined in claim 9, wherein the reflectivity in one of said spectral bands from said articles is substantially uniform to normalize the relative size of said articles to the size of said background.
 24. The invention defined in claim 10, wherein the reflectivity in one of said spectral bands from said articles is substantially uniform to normalize the relative size of said articles to the size of said background.
 25. The invention defined in claim 11, wherein the reflectivity in one of said spectral bands from said articles is substantially uniform to normalize the relative size of said articles to the size of said background.
 26. The invention defined in claim 12, wherein the reflectivity in one of said spectral bands from said articles is substantially uniform to normalize the relative size of said articles to the size of said background.
 27. The invention defined in claim 14, wherein said divisions of relative brightness and color tones comprise a bright and dark division line and two color division lines, said division lines intersecting to define said quality zones; and adjusting means in said control means constraining said division lines in selectively oriented relative positions to vary selectively the color characteristics defined by each said zone.
 28. The invention defined in claim 27, wherein said control means further includes logic means responsive to said adjusting means constraining said modulating means to correlate said scalar multipliers with said orientation of said division lines.
 29. The invention defined in claim 14, wherein said summing means includes integrating means sequentially integrating said third parameter for each said spectral band over respectively predetermined intervals correlated to said respective scalar multipliers and storing the sum of such integrations in discreet storage means correlated to each of said division lines; and said control means further including sampling means constraining said discreet storage means to apply said sums of said third parameters to said comparison means in synchronism with the respective correlated comparison parameters for said division lines.
 30. The invention defined in claim 29, wherein said divisions of relative brightness and color tones comprise a bright and dark division line and two color division lines, and division lines intersecting to define said quality zones; and adjusting means in said control means constraining said division lines in selectively oriented relative positions to vary selectively the color characteristics defined by each said zone.
 31. The invention defined in claim 30, wherein said control means further includes logic means responsive to said adjusting means constraining said modulating means to correlate said scalar multipliers with said orientation of said division lines.
 32. The invention defined in claim 14, wherein said detector means provide a fourth output parameter for each said band representative of the intensity of reflected light in the absence of an article over said obverse face; said differential means presenting the difference in said second and fourth parameters to said summing means as modulated by said modulating means for each said band to the exclusion of the other said bands; said summing means including update storage means for storing said modulated difference in said second and fourth parameters; and update switch means selectively connecting said update storage means with said reference means to update the magnitude of said second parameter with said modulated difference in said second and fourth parameters for each said spectral band.
 33. The invention defined in claim 32, wherein said divisions of relative brightness and color tones comprise a bright and dark division line and two color division lines, said division lines intersecting to define said quality zones; and adjusting means in said control means constraining said division lines in selectively oriented relative positions to vary selectively the color characteristics defined by each said zone.
 34. The invention defined in claim 33, wherein said control means further includes logic means responsive to said adjusting means constraining said modulating means to correlate said scalar multipliers with said orientation of said division lines.
 35. The invention defined in claim 32, wherein said summing means includes integrating means sequentially integrating said third parameter for each said spectral band over respectively predetermined intervals correlated to said respective scalar multipliers and storing the sum or such integrations in discreet storage means correlated to each of said division lines; and said control means further including sampling means constraining said discreet storage means to apply said sums of said third parameters to said comparison means in synchronism with the respective correlated comparison parameters for said division lines.
 36. The invention defined in claim 35, wherein said divisions of relative brightness and color tones comprise a bright and dark division line and two color division lines, said division lines intersecting to define said quality zones; and adjusting means in said control means constraining said division lines in selectively oriented relative positions to vary selectively the color characteristics defined by each said zone.
 37. The invention defined in claim 36, wherein said control means further includes logic means responsive to said adjusting means constraining said modulating means to correlate said scalar multipliers with said orientation of said division lines.
 38. Means selectively grading articles by brightness and two color tones relative to predetermined standards as said articles traverse a background surface of known color illuminated by polychromatic light, comprising: detecting and calculating means receiving reflected light from said articles and said background in three distinct spectral bands R, F and I and deriving for each said article a linear summation of the intensities of reflected light in the form rR'' + fF'' + iI'', for determining brightness and each of said color tones, wherein r, f and i are predetermined scalar multipliers respectively associated with said bands and R'', F'' and I'' are functions of the intensity of reflected light in said bands from said articles and said background surface; control means generating said scalar multipliers and a brightness and two color tone standards comprising division lines in the form rR'' + fF'' + iI'' + or - d where d is a predetermined constant, said division lines intersecting to form a plurality of color quality zones; and means comparing said linear summations with the correlative ones of said brightness and color tone standards, determining the relative magnitudes of said summations to that of the quantity + or - d and identifying the color quality zones characterizing each said article as a function of said relative magnitudes.
 39. The invention defined in claim 38, wherein said grading means further includes selection means designating said quality zones as acceptable or unacceptable; and correlating means responsive to said comparing means and said selection means providing for each said article an acceptable or unacceptable indication.
 40. The invention defined in claim 39, wherein said articles traverse said background surface in a first ballistic path; and wherein said grading means further includes means constraining a said article into a second ballistic path in response to a unacceptable indication for said article from said correlating means.
 41. The invention defined in claim 38, wherein R'', F'' and I'' comprise the difference in magnitudes of the intensity of reflected light from said background alone and from said background with an article traversing same in each said spectral band.
 42. The invention defined in claim 41, wherein said grading means further includes selection means designating said quality zones as acceptable or unacceptable; and correlating means responsive to said comparing means and said selection means providing for each said article an acceptable or unacceptable indication.
 43. The invention defined in claim 42, wherein said articles traverse said background surface in a first ballistic path; and wherein said grading means further includes means constraining a said article into a second ballistic path in response to an unacceptable indication for said article from said correlatig means.
 44. The invention defined in claim 38, wherein the reflectivity in one of said spectral bands from said articles is substantially uniform to normalize the relative size of said articles to the size of said background.
 45. The invention defined in claim 39, wherein the reflectivity in one of said spectral bands from said articles is substantially uniform to normalize the relative size of said articles to the size of said background.
 46. The invention defined in claim 40, wherein the reflectivity in one of said spectral bands from said articles is substantially uniform to normalize the relative size of said articles to the size of said background.
 47. The invention defined in claim 41, wherein the reflectivity in one of said spectral bands from said articles is substantially uniform to normalize the relative size of said articles to the size of said background.
 48. The invention defined in claim 42, wherein the refelectivity in one of said spectral bands from said articles is substantially uniform to normalize the relative size of said articles to the size of said background.
 49. The invention defined in claim 43, wherein the reflectivity in one of said spectral bands from said articles is substantially uniform to normalize the relative size of said articles to the size of said background.
 50. Means selectively grading articles by brightness and two color tones relative to predetermined standards as said articles traverse one or more background surfaces of known color illuminated by polychromatic light comprising: at least one detecting and calculating means associated with each said background surface receiving reflected light from said articles and said background in three distinct spectraL bands R, F and I and deriving for each said article a linear summation of the intensities of reflected light in the form rR'' + fF'' + iI'', for determining brightness and each of said color tones, wherein r, f and i are predetermined scalar multipliers respectively associated with said bands and R'', F'' and I'' are functions of the intensity of reflected light in said bands from said articles and said background surface; control means common to all said detecting and calculating means generating said scalar multipliers and a brightness and two color tone standards comprising division lines in the form rR'' + fF'' + iI'' + or - d where d is a predetermined constant, said division lines intersecting to form a plurality of color quality zones; means in each said detecting and calculating means comparing said linear summations with the correlative ones of said brightness and color tone standards, determining the relative magnitudes of said summations to that of the quantity + or - d and identifying the color quality zones characterizing each said article as a function of said relative magnitudes; and encoding means for each detecting and calculating means encoding and storing data characterizing said quality zone identities.
 51. The invention defined in claim 50, wherein said grading means further includes: selection means common to all said detecting and calculating means designating said quality zones as acceptable or unacceptable; sequencing means in said control means coordinating said detecting and calculating means, said comparing means, and said encoding means and sequentially shifting said encoded zone data through said selection means from each said encoding means to identify said zone data therefrom as characterizing acceptable or unacceptable zones.
 52. The invention defined in claim 51, wherein said selection means provides acceptable and unacceptable output indications in response to said encoded zone data for each said encoding means; and wherein said grading means further includes instruction generating means responsive to said output indications providing instructions to each said detecting and calculating means to accept and reject said acceptable and unacceptable articles, respectively.
 53. The invention defined in claim 50, wherein said articles traverse said background surface in a first ballistic path; and wherein said grading means further includes, for at least each said background surface, means constraining a said article into a second ballistic path in response to an unacceptable indication for said article from said correlating means.
 54. The invention defined in claim 51, wherein said articles traverse said background surface in a first ballistic path; and wherein said grading means further includes, for at least each said background surface, means constraining a said article into a second ballistic path in response to an unacceptable indication for said article from said correlating means.
 55. The invention defined in claim 52, wherein said articles traverse said background surface in a first ballistic path; and wherein said grading means further includes, for at least each said background surface, means constraining a said article into a second ballistic path in response to an unacceptable indication for said article from said correlating means.
 56. The invention defined in claim 50, wherein R'', F'' and I'' comprise the difference in magnitudes of the intensity of reflected light from said background alone and from said background with an article traversing same in each said spectral band.
 57. The invention defined in claim 51, wherein R'', F'' and I'' comprise the difference in magnitudes of the intensity of reflected light from said background alone and from said background with an article traversing saMe in each said spectral band.
 58. The invention defined in claim 52, wherein R'', F'' and I'' comprise the difference in magnitudes of the intensity of reflected light from said background alone and from said background with an article traversing same in each said spectral band.
 59. The invention defined in claim 53, wherein R'', F'' and I'' comprise the difference in magnitudes of the intensity of reflected light from said background alone and from said background with an article traversing same in each said spectral band.
 60. The invention defined in claim 54, wherein R'', F'' and I'' comprise the difference in magnitudes of the intensity of reflected light from said background alone and from said background with an article traversing same in each said spectral band.
 61. The invention defined in claim 55, wherein R'', F'' and I'' comprise the difference in magnitudes of the intensity of reflected light from said background alone and from said background with an article traversing same in each said spectral band.
 62. The invention defined in claim 50, wherein the reflectivity in one of said spectral bands from said articles is substantially uniform to normalize the relative size of said articles to the size of said background.
 63. The invention defined in claim 51, wherein the reflectivity in one of said spectral bands from said articles is substantially uniform to normalize the relative size of said articles to the size of said background.
 64. The invention defined in claim 52, wherein the reflectivity in one of said spectral bands from said articles is substantially uniform to normalize the relative size of said articles to the size of said background.
 65. The invention defined in claim 53, wherein the reflectivity in one of said spectral bands from said articles is substantially uniform to normalize the relative size of said articles to the size of said background.
 66. The invention defined in claim 54, wherein the reflectivity in one of said spectral bands from said articles is substantially uniform to normalize the relative size of said articles to the size of said background.
 67. The invention defined in claim 55, wherein the reflectivity in one of said spectral bands from said articles is substantially uniform to normalize the relative size of said articles to the size of said background.
 68. The invention defined in claim 56, wherein the reflectivity in one of said spectral bands from said articles is substantially uniform to normalize the relative size of said articles to the size of said background.
 69. The invention defined in claim 57, wherein the reflectivity in one of said spectral bands from said articles is substantially uniform to normalize the relative size of said articles to the size of said background.
 70. The invention defined in claim 58, wherein the reflectivity in one of said spectral bands from said artiles is substantially uniform to normalize the relative size of said articles to the size of said background.
 71. The invention defined in claim 59, wherein the reflectivity in one of said spectral bands from said articles is substantially uniform to normalize the relative size of said articles to the size of said background.
 72. The invention defined in claim 60, wherein the reflectivity in one of said spectral bands from said articles is substantially uniform to normalize the relative size of said articles to the size of said background.
 73. The invention defined in claim 61, wherein the reflectivity in one of said spectral bands from said articles is substantially uniform to normalize the relative size of said articles to the size of said background.
 74. Means selectively grading articles by brightness and two color tones relative to predetermined standards as said articles traverse a background surface of known color illuminated by polychromatic light and wherein said light is driven by an alternating current source, compRising: detecting and calculating means performing calculations for brightness and said two color tones of each said article in each of two consecutive half cycles of said alternating current source; logic means controlling said detecting and calculating means constraining storage of said calculations in the first said half cycle, a reverse logic for said calculations in the second said half cycle, and a summation of like ones of said first and second half cycle calculations; said summation, for each such calculation, providing resultant calculations for said brightness and said color tones compensated for alternating current induced variations in said polychromatic light and operating offsets in said detecting and calculating means; and means comparing said summations to said predetermined standards.
 75. The invention defined in claim 74, wherein said detecting and calculating means includes summing means effecting said summations comprising: integrating means including an integration capacitor consecutively storing each of said first and second half cycle calculations; storage capacitors means for each of said first half cycle calculations; first switch means selectively transferring each of said first half cycle calculations from said integration capacitor to a corresponding storage capacitor as each said calculation is completed; and second switch means selectively converting said integrating means to an amplifier means subsequent to each of said second half cycle calculation and constraining said summation of said like first and second half-cycle calculations, sequentially, and the application of said summations, in sequence, to said comparing means.
 76. Means grading and sorting tobacco leaves in reference to predetermined standards of brightness, greenness and redness, comprising: a background surface of known color; conveyor means constraining tobacco leaves to traverse the obverse face of said background surface; optical means impinging said obverse face and said leaves with polychromatic light and receiving reflected light therefrom in red, green and infrared bands of the spectrum; control means providing first, second and third reference parameters representative of the said standards of brightness, greenness and redness, respectively; calculating means responsive to said reflected light received by said optical means providing first, secoud and third operating parameters representative of the brightness, greenness and redness, respectively, of each said leaf traversing said obverse face of said background; comparator means responsive to said control means and said calculating means providing first, second and third resultant parameters representing, respectively, the relative brightness, greenness and redness of said leaves to said standards; and reject selection means operating on said leaves in response to said resultant parameters when the latter represent predetermined deviations from said standards.
 77. The invention defined in claim 76, wherein said reference parameters mutually define a plurality of color quality zones; and wherein said reject selection means includes zone selecting means selectively establishing said zones as said predetermined deviations from said standards.
 78. The invention defined in claim 76, wherein said tobacco leaves traverse said obverse face of said background surface in a predetermined first ballistic path; and wherein said reject selection means includes rejecting means responsive to the occurrence of said predetermined deviations constraining said leaves into a second predetermined ballistic path.
 79. The invention defined in claim 77, wherein said tobacco leaves traverse said obverse face of said background surface in a predetermined first ballistic path; and wherein said reject selection means includes rejecting means responsive to the occurrence of said predetermined deviations constraining said leaves into a secoNd predetermined ballistic path.
 80. Transducer means for classifying an object with reference to allowable deviations from predetermined standards of brightness and first and second color tones, comprising: a background surface of known color having an obverse face over which said object is positioned; optical means impinging said obverse face and said object with polychromatic light and receiving reflected light therefrom in three distinct bands of the spectrum; control means providing first, second and third reference parameters representative of the said standards of brightness and first and second color tones, respectively; calculating means respective to said reflected light received by said optical means providing first, second and third operating parameters representative of the brightness and first and second color tones, respectively, of said object; comparator means responsive to said control means and said calculating means providing first, second and third resultant parameters representing, respectively, the relative brightness and first and second color tones of said object to said standards; and means responsive to said resultant parameters to indicate when at least one of said relative brightness and first and second color tones of said object exceeds the corresponding one of said allowable deviations from said predetermined standards.
 81. Means classifying a succession of objects with reference to allowable deviations from predetermined standards of brightness and first and second color tones, comprising: a background surface of known color having an obverse face over which said objects are successively positioned; optical means impinging said obverse face and said objects with polychromatic light and receiving reflected light therefrom in first, second and third bands of the spectrum; control means providing first, second and third reference parameters representative of the said standards of brightness and first and second color tones, respectively; calculating means responsive to said reflected light received by said optical means providing first, second and third operating parameters representative of the brightness and first and second color tones, respectively, of each said object over said obverse face of said background; comparator means responsive to said control means and said calculating means providing first, second, and third resultant parmeters representing, respectively, the relative brightness and first and second color tones of said objects to said standards; and means responsive to said resultant parameters for each said object to indicate when at least one of said relative brightness and first and second color tones of a said object exceeds the corresponding one of said allowable deviations from said predetermined standards.
 82. The invention defined in claim 81 wherein one of said spectral bands is characterized by substantially uniform reflection from each of said succession of objects to normalize the size of said objects to that of said background. 